A longitudinal study in youth of heart rate variability at rest and in response to stress

Differential effects of sound interventions tuned to 432 Hz or 443 Hz on cardiovascular parameters in cancer patients: a randomized cross-over trial

BACKGROUND

This study investigated whether a sound intervention tuned to 432 Hz (Hz) yields differential effects on cardiovascular parameters and psychological outcomes compared to 443 Hz, which is the concert pitch in German professional orchestras.

METHODS

Using a randomized cross-over design, patients with cancer were recruited to receive both a 15-minute sound intervention with a body monochord tuned to 432-443 Hz. Before (pre) and after (post) intervention, cardiovascular parameters were measured using the VascAssist2.0. In addition, visual analogue scales (VAS) for emotional well-being, anxiety, stress, pain and sadness were also assessed pre and post intervention.

RESULTS

43 patients (8 male, 35 female) with a median age of 61 years (range 35-86) were included. Both interventions led to a significant reduction in heart rate with a more pronounced effect for 432 Hz (median reduction - 3 bpm (432 Hz) vs. median reduction - 1 bpm (443 Hz), p = 0.04). While heart rate variability was increased exclusively by 432 Hz (median increase + 3 ms, p = 0.01), both vascular resistance (median reduction - 5%, p = 0.008) and stiffness (median reduction %, p = 0.04) were significantly reduced by 432 Hz, which was not observed at 443 Hz. Nevertheless, these effects were not significantly different compared to 443 Hz. On the other hand, 432 Hz led to a reduced pulse wave velocity (median reduction - 0.5 m/s, p < 0.001), which was also significantly different compared to 443 Hz (p < 0.001). Improvement in VAS was observed for both groups, with significant increases in emotional well-being and reduction in fatigue, anxiety and stress for both intervention timepoints, although the majority showed no increased VAS scores even before the intervention (median values 0 for anxiety and stress).

CONCLUSION

Sound interventions tuned to 432-443 Hz exert both positive effects in cancer patients. While psychological outcomes are improved by both interventions, 432 Hz leads to a more pronounced but not significantly different effect to 443 Hz on objective cardiovascular parameters, which reflect deeper relaxation.

Impact of exhaustive exercise on autonomic nervous system activity: insights from HRV analysis

Introduction

Exhaustive exercise is a common training method in sports, but its impact on the autonomic nervous system of the human body remains unclear. Understanding the effects of exhaustive exercise on the body and its connection with the autonomic nervous system and central nervous system is crucial for guiding healthy training methods.

Methods

Twenty-three participants were selected, and exhaustive exercise intervention was performed using the Bruce Protocol. By measuring heart rate variability (HRV), the effects of exhaustive exercise on the autonomic nervous system function were analyzed.

Results

After exhaustive exercise, time-domain indices SDNN, RMSSD, and PNN50 all significantly decreased, with changes reaching significant levels (p < 0.01). Among them, the decrease in pNN50 was particularly pronounced, with a change rate of -94.55%. Frequency-domain indices VLF, LF, and HF also showed significant decreases (p < 0.01), but the ratio of LF to HF showed an upward trend (p < 0.01), with LF showing a greater decrease. Nonlinear indices SD1 and SD2 showed extremely significant decreases (p < 0.01), and the SD2/SD1 ratio showed a significant increase (p < 0.01), indicating significant changes in HRV nonlinear characteristics after exercise.

Discussion

Exhaustive exercise leads to a decrease in autonomic nervous system activity and an increase in sympathetic nervous system activity. These findings underscore the profound impact of exhaustive exercise on the autonomic nervous system, with implications for understanding the physiological responses to intense physical exertion. Further research is warranted to explore the long-term effects of exhaustive exercise on autonomic regulation and its potential implications for training methodologies and athlete health.

Moderate cardiac vagal tone predicts more cooperation in highly sensitive individuals

Cooperation, as a mutual collaboration, is a defining feature of human social life. Individual characteristics can influence cooperation. Recent studies have shown a quadratic relationship between cardiac vagal tone (CVT), an index of self-regulation, and prosocial behaviors. Individual differences in cooperation might also vary as a function of people's environmental sensitivity (ES), i.e., may be influenced by individual differences in the perception and processing of inner and external stimuli. We tested the direct and interactive effect of CVT and ES on cooperative behaviors in two independent samples. We measured heart rate and engagement in cooperative acts in 80 young adults (M = 23.61; SD = 1.60) who were also asked to self-report on ES. We found an inverted-U relationship between CVT and cooperative behaviors. ES, on the other hand, did not predict differences in cooperative behaviors but moderated the relationships between CVT and cooperation, although the magnitude of this result was small. Specifically, only among individuals with higher ES cooperative behaviors change as a function of CVT. Highly sensitive individuals with lower or higher CVT, were less cooperative than low sensitive ones. Subsequently, we replicated the same study design in a second sample of 88 undergraduate students (M = 23.69; SD = 4.91). Once again, we found evidence supporting the presence of an inverted-U relationship between CVT and cooperative behaviors, and we also found that ES moderated the relationships between the quadratic CVT term and cooperation.

Insight and non-insight problem solving: A heart rate variability study

Occasionally, problems are solved with a sudden Aha! moment (insight), while the mundane approach to solving problems is analytical (non-insight). At first glance, non-insight appears to depend on the availability and taxation of cognitive resources to execute the step-by-step approach, whereas insight does not, or to a lesser extent. However, this remains debated. To investigate the reliance of both solution types on cognitive resources, we assessed the involvement of the prefrontal cortex using vagally mediated heart rate variability (vmHRV) as an index. Participants (N = 68) solved 70 compound remote associates word puzzles solvable with insight and non-insight. Before, during, and after solving the word puzzles, we measured the vmHRV. Our results showed that resting-state vmHRV (trait) showed a negative association with behavioural performance for both solution types. This might reflect inter-individual differences in inhibitory control. As the solution search requires one to think of remote associations, inhibitory control might hamper rather than aid this process. Furthermore, we observed, for both solution types, a vmHRV increase from resting-state to solution search (state), lingering on in the post-task recovery period. This could mark the increase of prefrontal resources to promote an open-minded stance, essential for divergent thinking, which arguably is crucial for this task. Our findings suggest that, at a general level, both solution types share common aspects. However, a closer analysis of early and late solutions and puzzle difficulty suggested that metacognitive differentiation between insight and non-insight improved with higher trait vmHRV, and that a unique association between trait vmHRV and puzzle difficulty was present for each solution type.

Hemodynamic and Stress Response After Sound Intervention with Different Headphone Systems: A Double-Blind Randomized Study in Healthy Volunteers Working in the Health Care Sector

Objectives: Two headphone systems using different sound systems were compared to investigate the effects of a sound intervention on cardiovascular parameters, indicators of stress, and subjective feelings. Methods: One hundred volunteers who work in the health care sector reporting elevated workplace-related stress were enrolled and randomized to a 12-min sound intervention (classical music) with either conventional headphones ("MEZE 99 Classic") or with the same-but internally modified-headphone (called "Lautsaenger"). Cardiovascular parameters were measured with the VascAssist2.0, both before and after sound interventions. In addition, participants were asked to complete questionnaires on burnout risk and emotions/stress. Results: The study population consisted mainly of female participants (n = 83), with the majority being students (42%). Median age was 32.5 years (range 21-71). In terms of cardiovascular parameters, a significant reduction in aortic pulse wave velocity, as measure of arterial stiffness, and heart rate was observed within both treatment arms. Both systolic blood pressure and arterial flow resistance were reduced by sound intervention, while these effects were only documented with Lautsaenger. Treatment groups were comparable in terms of subjective feedback by participants: a significant increase in emotional wellbeing was achieved with both headphone systems. Conclusions: A single short-term sound intervention seems to be able to achieve objective cardiovascular improvements in healthy volunteers reporting subjective symptoms of workplace-related stress, using two different headphone systems. Moreover, significant emotional improvement was reported within both arms. Trial Registration: ISRCTN registry 70947363, date of registration August 13, 2021.

Heart Rate Variability in Concussed College Athletes: Follow-Up Study and Biological Sex Differences

Finding reliable biomarkers to assess concussions could play a pivotal role in diagnosis, monitoring, and predicting associated risks. The present study aimed to explore the use of heart rate variability (HRV) in the follow-up of concussions among college athletes and to investigate the relationships between biological sex, symptomatology, and HRV values at baseline and after a concussion. Correlations between measures were also analyzed. A total of 169 (55 females) athletes aged 16 to 22 years old completed baseline testing, and 30 (8 females) concussion cases were followed. Baseline assessment (T1) included psychosocial and psychological questionnaires, symptoms report, and four minutes of HRV recording. In the event of a concussion, athletes underwent re-testing within 72 h (T2) and before returning to play (T3). Baseline findings revealed that girls had higher %VLF while sitting than boys, and a small negligible correlation was identified between %HF and total symptoms score as well as %HF and affective sx. Post-concussion analyses demonstrated a significant effect of time × position × biological sex for %HF, where girls exhibited higher %HF at T3. These findings suggest disruptions in HRV following a concussion and underscore biological sex as an important factor in the analysis of HRV variation in concussion recovery trajectory.

Resilience to stress across the lifespan: Childhood maltreatment, heart rate variability, and bereavement

Following a stressful life event, there is considerable variation in how individuals respond and adapt. Multiple models of risk and resilience show that adverse childhood experiences may be associated with an individual's response to stress later in life. While there is considerable support that early adversity can sensitize the stress response system and lead to adverse outcomes later in life, there is mounting evidence that in adolescence and young adulthood, certain biological predispositions to stress may be associated with resilience in the context of subsequent stressors. In this study, we evaluated how individual differences in vagally mediated heart rate variability moderated the relationship between childhood maltreatment and grief among a sample of individuals experiencing a stressful life event (i.e., spousal bereavement) over time. Data were collected at approximately 3, 4.5, and 6.5 months after the death of a spouse (n = 130). Heart rate variability moderated the relationship between childhood maltreatment and grief symptoms over time (b = -0.03, p < .001), such that among individuals with more severe experiences of childhood maltreatment, those with higher heart rate variability had a faster recovery from grief than those with low heart rate variability. This research highlights an overall pattern of resilience among older adult's following spousal bereavement, as well as the relationships between childhood maltreatment, heart rate variability, and differential responses to grief following the loss of a spouse. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

A Systematic Review of Clinical Psychophysiology of Obsessive-Compulsive Disorders: Does the Obsession with Diet Also Alter the Autonomic Imbalance of Orthorexic Patients?

(1) Background: A new mental illness is attracting the attention of researchers and mental health professionals. Orthorexia nervosa (ON) is a possible new mental disorder, the main symptom of which is an obsessive and insecure focus on healthy foods and consequent compulsive behaviors. There is a common consensus among researchers that ON is considered partly overlapping with obsessive-compulsive disorders (OCDs). (2) Methods: MEDLINE and Scopus were searched for articles published in the last 10 years regarding the psychophysiological aspects of OCD and ON. Eight studies met the eligibility criteria. The inclusion criteria encompassed adults diagnosed with OCD and/or ON. However, only studies involving OCD patients were found. (3) Results: Some research groups have shown that OCD disorders can be considered among anxiety disorders because they are characterized by anxious hyper activation. Other research, however, has shown profiles characterized by low psychophysiological reactivity to stressful stimuli. Despite this, there seems to be a consensus on the poor inhibition abilities, even when activation is low, and the dissociation between cognitive and psychophysiological activation emerged. (4) Conclusions: However discordant, some points seem to bring the researchers to agreement. In fact, there is consensus on conducting a multidimensional assessment that can measure all of the aspects of suffering (cognition, emotion, and behavior) and highlight the poor body-mind integration. This clinical approach would make it possible to propose interventions aimed at treating some mental illnesses such as food obsession that can paradoxically impair the psychophysical balance. Nevertheless, the applied systematizing approach to existing studies on ON is very much needed for better understanding of the psychophysical nature of this new mental illness and its implications for prevention and treatment.

Psychophysiological Stress Status of Soldiers Prior to an Operative Deployment

An anticipatory stress response develops before an internal or external stimulus, which initiates a homeostasis process through a chain of responses that enable human organisms to face different threats, thus allowing them to adapt to a continuous and eliciting environment. In the current research, we analyzed the psychophysiological anticipatory anxiety response of professional soldiers prior to a real mission in an actual theater of operation. Autonomic modulation through the heart rate variability values, muscular strength manifestation, and psychological stress of 53 military personnel of Army Airmobile Forces (age: M = 35.4 years, SD = 5.88 years; height: M = 1.75 m, SD = 6.87 cm; body mass: M = 77.33 kg, SD = 11.95 kg; military duty = 14.44 years, SD = 6.43; military operation experience = 4 months, SD = 4.25 months) and a control group of 33 civil participants were analyzed. The military personnel presented significant differences in some HRV values related to the activation of sympathetic systems. We found that the military personnel presented an anticipatory anxiety response only at an autonomic level, showing an increased sympathetic modulation, but not at a psychological level, since their anxiety levels were not significantly different than those of the control civilians. In addition, this anticipatory anxiety response did not affect muscular strength manifestation, as it presented no significant differences between the military personnel and the control group.

Can you feel the excitement? Physiological correlates of students' self‐reported emotions

BACKGROUND

This study explored the physiological correlates of students' self-reported emotions in ecologically valid settings by combining biosignal data (on physical and cardiac activity) and experience sampling method (ESM) data.

AIMS

The aim was to examine the concurrent associations between self-reported excitement, calmness, anxiety, and boredom (adopted from the dimensional model of emotions) and students' heart rate (HR) and heart rate variability (HRV) (indicators of physiological arousal and the activation of the autonomous nervous system). Students' physical activity was controlled in the models via the metabolic equivalent of task (MET) values (actigraphy data). A second objective was to explore how to combine the information stored by these three sources of ambulatory assessment.

SAMPLE

The study comprised 136 high school students with multiple repetitive data points.

METHODS

For three consecutive days, students wore biometric sensors and wristbands collecting their HR, HRV, and MET signals, and answered the ESM questionnaires five times a day on smartphones.

RESULTS

When MET values were controlled for, self-reported excitement was related to higher HR as well as lower HRV during a specific moment, indicating stronger sympathetic activity (i.e., physiological arousal/activation). Self-reported boredom was related to lower HR but was unrelated to HRV. Self-reported calmness and anxiety were unrelated to HR and HRV after controlling for MET.

CONCLUSIONS

A 5-min time window with a Gaussian weighted mean seemed to be an appropriate data processing method for capturing the physiological arousal (or abate) of self-reported excitement and boredom. The findings suggest that the physiological stimulus of elevated HR could be interpreted by students as an adaptive state of excitement. Combining the experience sampling approach and the physiological measures revealed how the mind and body function in interplay and can therefore provide objective evidence of emotional and motivational processes as they unfold in students' daily lives.

Determining the direction of prediction of the association between parasympathetic dysregulation and exhaustion symptoms

Stress-related exhaustion symptoms have a high prevalence which is only likely to increase further in the near future. Understanding the physiological underpinnings of exhaustion has important implications for accurate diagnosis and the development of effective prevention and intervention programs. Given its integrative role in stress-regulation, the parasympathetic branch of the autonomic nervous systems has been a valid starting point in the exploration of the physiological mechanisms behind exhaustion. The aim of the present study was to examine the directionality and specificity of the association between exhaustion symptoms and vagally-mediated heart rate variability (vmHRV), a relatively pure measure of parasympathetic tone. Exhaustion symptoms and vmHRV were measured at four annually assessment waves (2015-2018) of the Dresden Burnout Study. A total sample of N = 378 participants who attended at least two of the four annual biomarker measurements were included in the present analyses. Cross-lagged multi-level panel modelling adjusting for various covariates (e.g., age, sex, BMI) revealed that vmHRV was meaningfully predictive of exhaustion symptoms and not vice versa. In addition, these effects were specific for exhaustion symptoms as no effect was shown for the other burnout sub-dimensions, or for depressive symptoms. Our findings indicate a clear link between exhaustion symptoms and vmHRV which may hold great potential for both enhancing the diagnosis and treatment of exhaustion symptoms.

Self-Compassion and Its Association With Ruminative Tendencies and Vagally Mediated Heart Rate Variability in Recurrent Major Depression

Background

Recurrent Major Depressive Disorder (MDD) is one of the most disabling mental disorders in modern society. Prior research has shown that self-compassion protects against ruminative tendencies, a key feature of recurrent MDD. In addition, self-compassion has been found to be positively related to higher psychophysiological flexibility (indexed by a higher vagally mediated heart rate variability; vmHRV) in young, healthy adults. To our knowledge, there is a lack of studies on how self-compassion relates to vmHRV in patients with recurrent MDD. The aim of the current study was to investigate whether higher self-compassion would associate with (1) lower ruminative tendencies and (2) higher vmHRV in a sample of adults with recurrent MDD.

Methods

We included a sample of 63 patients (46 females) between 20 and 71 years old (M = 40.24, SD = 12.8) with a history of three or more depressive episodes. They filled out the Self-Compassion Scale (SCS), Beck Depression Inventory (BDI), and Rumination Rating Scale (RRS). ECG (used to derive vmHRV) was acquired while resting and the square root of the mean squared differences of successive RR interval values (RMSSD) was calculated as measure of vmHRV.

Results

As hypothesized, self-compassion was associated with lower ruminative tendencies. However, self-compassion was not associated with level of vmHRV. Several confounding variables were controlled for in the statistical analyses, and higher age predicted lower vmHRV across all statistical analyses.

Conclusion

The results confirmed our hypothesis that higher self-compassion would be associated with lower ruminative tendencies in recurrent MDD. Contrary to our expectation, we did not find that the tendency to be more self-compassionate was associated with higher vmHRV. As such, higher self-compassion seems to relate with a lower tendency to ruminate about past mistakes and events but does not seem to relate to a flexible autonomic stress response (as indexed by higher vmHRV). Other potential explanatory factors for lower vmHRV in recurrent MDD is suggested as focus for exploration in future studies.

Improvement in parasympathetic regulation is associated with engagement in classroom activity in primary school children experiencing poor classroom climate

BACKGROUND

Self-regulation promotes engagement within the classroom. At a physiological level, a good indicator of the ability of the system to self-regulate is cardiac vagal tone (CVT).

AIMS

The present study aims to assess children's change over time (1 year) in their parasympathetic regulation (by way of CVT) in response to a social and cognitive stressor. Moreover, it addresses whether, if present, this change over time in regulation influences students' engagement in classroom activities while also accounting for classroom climate.

SAMPLE

Forty-nine second graders were assessed at two time points: November 2018 (T1) and 1 year later in 2019 (T2).

METHODS

Children's CVT was registered at rest and while performing a stressful task during which they were asked to cognitively perform while being socially evaluated. Children were also interviewed on how much they feel engaged in classroom activities and their perceptions of classroom climate.

RESULTS

A repeated measures analysis of variance including 2 Time Points ×2 Phases of CVT Registration (baseline and during the stressful task) revealed a significant decrease in cardiac vagal activity from baseline to the task at T1, indicating that initially most children were not able to self-regulate and gave way to a stress response when facing the stressful task. The pattern changed at T2 when an active regulation took place signalled by an increase in CVT from baseline to the stressful task. Data analysis also revealed that among children who perceived a poorer classroom climate, the display of greater parasympathetic regulation over time was linked with higher active engagement in classroom activities.

CONCLUSIONS

Growth in physiological regulation in response to a challenging task is associated with better engagement in classroom activities. Interventions and educational practice promoting the development of self-regulation strategies are recommended.

Reading with induced worry: The role of physiological self-regulation and working memory updating in text comprehension

BACKGROUND

An interplay of emotional and cognitive aspects underlies academic performance. We focused on the contribution of such interplay to text comprehension.

AIMS

We investigated the effect of worry on comprehension and the role of two potential moderators of this effect: physiological self-regulation as resting heart rate variability (HRV) and working memory updating.

SAMPLE

Eighty-two seventh graders were involved in a quasi-experimental design.

METHODS

Students read an informational text in one of two reading conditions: to read for themselves to know more (n = 46; low-worry condition) or to gain the highest score in a ranking (n = 36; high-worry condition). Students' resting HRV was recorded while watching a video of a natural scenario. The executive function of working memory updating was also assessed. After reading, students completed a comprehension task.

RESULTS

Findings revealed the moderating role of HRV in the relationship between induced worry and text comprehension. In the high-worry condition, students with higher resting HRV performed better than students who read under the same instructions but had lower HRV. In contrast, in the low-worry condition, students with higher resting HRV showed a lower performance as compared to students with lower HRV. Finally, working memory updating was positively related to text comprehension.

CONCLUSIONS

Our findings indicate that the cognitive component of anxiety, that is, worry, plays a role in performing a fundamental learning activity like text comprehension. The importance of physiological self-regulation emerges clearly. In a condition of high worry, higher ability to regulate emotions and thoughts acts as a protective factor.

Chronic stress, autonomic dysregulation and prospective drug use among African American emerging adults

OBJECTIVE

Chronic stress is associated with increased vulnerability to drug use and may contribute to drug-related health disparities in the African American community. The underlying physiological mechanisms by which chronic stress confers this increased risk remain unclear. The present study aimed to characterize the impact of chronic and race-related stress exposure on regulatory mechanisms of the autonomic nervous system (ANS) in response to acute stress, to examine John Henryism as potential moderator of this relationship, and to investigate the association between ANS reactivity and subsequent drug use among a sample of African American emerging adults (18-25 years old) in the Southern United States (U.S.).

METHOD

Participants (N = 276) completed self-report measures of chronic and race-related stress and John Henryism and underwent a laboratory-based stressor. ANS reactivity was assessed via heart rate variability (HRV) and skin conductance levels (SCL). At 90-day follow-up, retrospective reports of drug use were provided.

RESULTS

Race-related stress was associated with greater SCL reactivity. John Henryism moderated the relationship between chronic stress exposure and HRV reactivity. SCL reactivity was associated with higher rates of alcohol and marijuana use at 90-day follow-up. HRV reactivity was associated with tobacco use at 90-day follow-up.

CONCLUSIONS

Chronic stress exposure and active coping may interact to affect regulatory mechanisms of the ANS. ANS (dys)regulation may be an important endophenotype for increasing drug use vulnerability among African American emerging adults. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Evaluating commercially available wireless cardiovascular monitors for measuring and transmitting real-time physiological responses in children with autism

Commercially available wearable biosensors have the potential to enhance psychophysiology research and digital health technologies for autism by enabling stress or arousal monitoring in naturalistic settings. However, such monitors may not be comfortable for children with autism due to sensory sensitivities. To determine the feasibility of wearable technology in children with autism age 8-12 years, we first selected six consumer-grade wireless cardiovascular monitors and tested them during rest and movement conditions in 23 typically developing adults. Subsequently, the best performing monitors (based on data quality robustness statistics), Polar and Mio Fuse, were evaluated in 32 children with autism and 23 typically developing children during a 2-h session, including rest and mild stress-inducing tasks. Cardiovascular data were recorded simultaneously across monitors using custom software. We administered the Comfort Rating Scales to children. Although the Polar monitor was less comfortable for children with autism than typically developing children, absolute scores demonstrated that, on average, all children found each monitor comfortable. For most children, data from the Mio Fuse (96%-100%) and Polar (83%-96%) passed quality thresholds of data robustness. Moreover, in the stress relative to rest condition, heart rate increased for the Polar, F(1,53) = 135.70, p < 0.001, ηp²  = 0.78, and Mio Fuse, F(1,53) = 71.98, p < 0.001, ηp²  = 0.61, respectively, and heart rate variability decreased for the Polar, F(1,53) = 13.41, p = 0.001, ηp²  = 0.26, and Mio Fuse, F(1,53) = 8.89, p = 0.005, ηp²  = 0.16, respectively. This feasibility study suggests that select consumer-grade wearable cardiovascular monitors can be used with children with autism and may be a promising means for tracking physiological stress or arousal responses in community settings. LAY SUMMARY: Commercially available heart rate trackers have the potential to advance stress research with individuals with autism. Due to sensory sensitivities common in autism, their comfort wearing such trackers is vital to gathering robust and valid data. After assessing six trackers with typically developing adults, we tested the best trackers (based on data quality) in typically developing children and children with autism and found that two of them met criteria for comfort, robustness, and validity.

Resting Heart Rate Variability, Perceived Emotion Regulation, and Low-Risk Drug Use in College-Aged Adults: Gender as a Moderator

Identification of individual differences in drug use is warranted, as a history of use is associated with future drug problems. Such drug use is thought to disrupt inhibitory and motivation networks involved in emotion regulation (ER). Higher resting heart rate variability (HRV), a biomarker of effective inhibitory abilities, is associated with less substance (e.g., alcohol, opioid) use. Higher HRV is associated with lower perceived ER difficulties, and this link is stronger in women relative to men. Evidence suggests women might engage in drug use primarily to reduce stress, and men primarily to induce feelings of elation. Research has yet to examine associations among individuals' difficulties in ER, resting HRV, and a recent history of drug use; the current study explored this, in addition to how these associations might differ as a function of gender. Young and healthy college students (N = 190; 88 women) completed a 5-min baseline to assess resting HRV, followed by the 36-item difficulties in ER Scale and 10-item Drug Abuse Screening Test. Higher difficulties in ER, but not resting HRV, were associated with a greater history of "low-risk" drug use in the full sample and moderation tests confirm this link was stronger in women. Moderated-mediation results confirmed an indirect association between resting HRV and drug use, mediated by self-reported difficulties among women only. A significant association between resting HRV and Difficulties in Emotion Regulation Scale (DERS) emerged only among women without a history of drug use. These results indicate that difficulties in ER are both associated with a low-risk history of drug use and underlie an indirect link between resting HRV and drug use history in women only. Among these women with a history of drug use relative to women without, there was no link between resting HRV and self-reported difficulties in ER, suggesting a disrupted inhibitory-motivational pathway. Additional work is needed to understand the psychophysiological correlates of a history of low-risk drug use in young men. These data are in line with research suggesting gender differences in the motivation to engage in recreational drug use and ER interventions might be important in women who engage in low-risk recreational drug use.

Vagally mediated heart rate variability, stress, and perceived social support: a focus on sex differences

Higher vagally mediated heart rate variability (vmHRV), reflecting vagal activity as indexed by heart function and lower stress vulnerability, is associated with higher perceived social support. Seeking social support is an adaptive stress response, and evolutionary theories suggest that females use this strategy more than males. The current study investigated the hypothesis that higher vmHRV is related to higher perceived social support under conditions of higher, relative to lower, stress, and that this association is most prominent in females. A healthy student sample (n = 143; 82 males, 61 females; mean age 19.9) completed the short version of the Medical outcomes study social support survey (MOS) and the Perceived stress scale (PSS). Activity in the high frequency band of heart rate variability (HF-HRV), deducted from five-minute resting electrocardiogram (ECG) recordings, indexed vmHRV. A moderation analysis was conducted, with PSS and sex as moderators of the association between vmHRV and MOS. Statistical effects were adjusted for age, education, physical activity, body mass index (BMI), alcohol and drug use, ECG-derived respiration (EDR), and mean heart rate. Higher PSS scores moderated the association between vmHRV and MOS in females but not males. Lower PSS scores did not moderate the relation between vmHRV and MOS. This suggests that higher vmHRV is associated with higher perceived social support under conditions of higher stress in females but not males, consistent with evolution of different stress management strategies in the sexes. The results may have implications for individualized intervention strategies for increasing vmHRV and perceived social support.

The interplay of self-critical rumination and resting heart rate variability on subjective well-being and somatic symptom distress: A prospective study

OBJECTIVE

The aim of this prospective study was to investigate the association of self-critical rumination, autonomic function (indexed by a time domain metric of resting heart rate variability-RMSSD), subjective well-being and somatic symptom distress.

METHOD

84 healthy participants (73 females; mean age = 23.56, SD = 3.35 years) completed the Somatic Symptom Severity Scale of the Patient Health Questionnaire and Mental Health Continuum Short Form at two timepoints (at baseline and six months later). Resting heart rate variability (HRV) was assessed at baseline, along with content specific rumination using the Self-Critical Rumination Scale. Four moderation analyses were performed to test these associations.

RESULTS

The interaction between resting HRV and self-critical rumination significantly explained somatic symptom distress at baseline. For those participants who had high resting HRV, somatic symptom distress was basically independent from the level of self-critical rumination. At the same time, lower resting HRV was associated with higher somatic symptom distress, especially in the presence of more ruminative thoughts. Prospectively, however, the interaction between rumination and resting HRV was not a significant predictor of somatic symptom distress. The association between resting HRV and self-critical rumination did not explain the variance on subjective well-being, but subjective well-being was negatively related to self-critical rumination.

CONCLUSION

Our findings potentially indicate that self-critical rumination could have a long-term negative impact on psychological functioning, even in a non-clinical sample, and highlight that a lower level of parasympathetic activation, assessed with RMSSD, might be an important factor in the relationship of self-critical rumination and somatic symptom distress.

Early life stress moderated the influence of reward anticipation on acute psychosocial stress responses

Recent studies suggest that reward anticipation decreases individuals' acute stress responses. However, individuals who have experienced early life stress (ELS) may have a blunted capacity for reward anticipation, which reduces its buffering effect on psychosocial stress responses. To investigate this phenomenon, 66 young adults completed the Trier Social Stress Test following a reward anticipation task, and their ELS levels were measured using the Childhood Trauma Questionnaire (CTQ). Meanwhile, the current study collected biological and psychological measures of stress by analysing cortisol levels, heart rates, heart rate variability (HRV) as well as subjective stress levels, in response to the Trier Social Stress test. Results showed that reward anticipation successfully decreased acute stress responses in general, and it also improved participants' HRV. However, this effect was more evident in individuals with low ELS than those with high ELS. These findings help us deepen understanding of the role of reward anticipation in fostering resilience under stress and the potentially important implications for individuals who have been exposed to ELS are also discussed.

Leaderboard Positions and Stress—Experimental Investigations into an Element of Gamification

Gamification, i.e., the use of game elements in non-game contexts, aims to increase peoples’ motivation and productivity in professional settings. While previous work has shown both positive as well as negative effects of gamification, there have been barely any studies so far that investigate the impact different gamification elements may have on perceived stress. The aim of the experimental study presented in this paper was thus to explore the relationship between (1) leaderboards, a gamification element which exchanges and compares results, (2) heart rate variability (HRV), used as a relatively objective measure for stress, and (3) task performance. We used a coordinative smartphone game, a manipulated web-based leaderboard, and a heart rate monitor (chest strap) to investigate respective effects. A total of n = 34 test subjects participated in the experiment. They were split into two equally sized groups so as to measure the effect of the manipulated leaderboard positions. Results show no significant relationship between the measured HRV and leaderboard positions. Neither did we find a significant link between the measured HRV and subjects’ task performance. We may thus argue that our experiment did not yield sufficient evidence to support the assumption that leaderboard positions increase perceived stress and that such may negatively influence task performance.

A Close Examination of the Use of Systolic Time Intervals in the Calculation of Impedance Derived Cardiac Autonomic Balance and Regulation

Traditionally, impedance derived measures of cardiac autonomic balance (CAB) and regulation (CAR) are calculated using indices of heart rate variability (HRV) that primarily reflect parasympathetic nervous system activity (e.g., high-frequency HRV | HF-HRV) and pre-ejection period (PEP; a systolic time interval and measure of sympathetic activity). However, HF-HRV and PEP are considered measures of chronotropic and inotropic cardiac influence, respectively. Left ventricular ejection time (LVET) is a systolic time interval that reflects sympathetic chronotropic influence, and therefore may be a more appropriate measure for calculating CAB and CAR compared to PEP. Thus, the current study evaluates both PEP and LVET in the calculation of CAB and CAR. Data from 158 healthy participants (mean age = 19.09 years old, SD = 1.84 years) were available for analyses. CAB and CAR values were calculated using both HF-HRV and the root mean square of successive differences, in addition to both PEP and LVET, in accordance with previously established guidelines. Analyses showed that correlations were significantly weaker between CAB and CAR calculated using LVET for both HF (z = 5.12, p < 0.001) and RMSSD (z = 5.26, p < 0.001) than with PEP. These data suggest that LVET, compared to PEP, provides better “autonomic space” as evidenced by a lack of correlation between CAB and CAR computed using LVET. We stress that future research consider calculating CAB and CAR using chronotropic measures for both parasympathetic and sympathetic activity, as doing so may yield more accurate and independent measures of cardiac autonomic activity compared to a mixture of inotropic (i.e., PEP) and chronotropic (i.e., HF-HRV) measures.

Impact of Water Temperature on Heart Rate Variability during Bathing

Background: Heart rate variability (HRV) is affected by many factors. This paper aims to explore the impact of water temperature (WT) on HRV during bathing. Methods: The bathtub WT was preset at three conditions: i.e., low WT (36–38 °C), medium WT (38–40 °C), and high WT (40–42 °C), respectively. Ten subjects participated in the data collection. Each subject collected five electrocardiogram (ECG) recordings at each preset bathtub WT condition. Each recording was 18 min long with a sampling rate of 200 Hz. In total, 150 ECG recordings and 150 WT recordings were collected. Twenty HRV features were calculated using 1-min ECG segments each time. The k-means clustering analysis method was used to analyze the rough trends based on the preset WT. Analyses of the significant differences were performed using the multivariate analysis of variance of t-tests, and the mean and standard deviation (SD) of each HRV feature based on the WT were calculated. Results: The statistics show that with increasing WT, 11 HRV features are significantly (p < 0.05) and monotonously reduced, four HRV features are significantly (p < 0.05) and monotonously rising, two HRV features are rising first and then reduced, two HRV features (fuzzy and approximate entropy) are almost unchanged, and vLF power is rising. Conclusion: The WT has an important impact on HRV during bathing. The findings in the present work reveal an important physiological factor that affects the dynamic changes of HRV and contribute to better quantitative analyses of HRV in future research works.

The validity and reliability of ultra-short-term heart rate variability parameters and the influence of physiological covariates

Ultra-short-term (UST) heart rate variability (HRV) metrics have increasingly been proposed as surrogates for short-term HRV metrics. However, the concurrent validity, within-day reliability, and between-day reliability of UST HRV have yet to be comprehensively documented. Thirty-six adults (18 males, age: 26 ± 5 yr, BMI: 24 ± 3 kg/m²) were recruited. Measures of HRV were quantified in a quiet-stance upright orthostatic position via three-lead electrocardiogram (ADInstruments, FE232 BioAmp). All short-term data recordings were 300 s in length and five UST time points (i.e., 30 s, 60 s, 120 s, 180 s, and 240 s) were extracted from the original 300-s recording. Bland-Altman plots with 95% limits of agreement, repeated measures ANOVA and two-tailed paired t tests demarcated differences between UST and short-term recordings. Linear regressions, coefficient of variation, intraclass correlation coefficients, and other tests examined the validity and reliability in both time- and frequency domains. No group differences were noted between all short-term and UST measures, for either time- (all P > 0.202) or frequency-domain metrics (all P > 0.086). A longer recording duration was associated with augmented validity and reliability, which was less impacted by confounding influences from physiological variables (e.g., respiration rate, carbon dioxide end-tidals, and blood pressure). Conclusively, heart rate, time-domain, and relative frequency-domain HRV metrics were acceptable with recordings greater or equal to 60 s, 240 s, and 300 s, respectively. Future studies employing UST HRV metrics should thoroughly understand the methodological requirements to obtain accurate results. Moreover, a conservative approach should be utilized regarding the minimum acceptable recording duration, which ensures valid/reliable HRV estimates are obtained.NEW & NOTEWORTHY A one size fits all methodological approach to quantify HRV metrics appears to be inappropriate, where study design considerations need to be conducted upon a variable-by-variable basis. The present results found 60 s (heart rate), 240 s (time-domain parameters), and 300 s (relative frequency-domain parameters) were required to obtain accurate and reproducible metrics. The lower validity/reliability of the ultra-short-term metrics was attributable to measurement error and/or confounding from extraneous physiological influences (i.e., respiratory and hemodynamic variables).

The longitudinal negative impact of early stressful events on emotional and physical well-being: The buffering role of cardiac vagal development

Early stressful events negatively affect emotional and physical well-being. Cardiac vagal tone (CVT), which is associated with better emotional and physical well-being, usually gradually increase in early childhood. Nonetheless, children's CVT developmental trajectories are greatly variable, such that CVT can increase or decrease across the years. The present study examines the longitudinal effects of early stressful events and the role of 4 years CVT developmental trajectory on children's emotional and physical well-being. Forty-two 4-year-old children were enrolled. Number of stressful events and resting electrocardiogram (ECG) were collected at T1. ECG was registered again after one (T2), two (T3) and three (T4) years. Children's emotional and physical well-being were assessed at T4 through the Child Health and Illness Profile - Child Edition (CHIP-CE). CVT development was calculated as the angular coefficient, reflecting the developmental trajectory of CVT across the four timepoints. Results yielded that higher experienced stressful events predicted poorer emotional and physical well-being after 4 years. The interaction between the number of stressful events and CVT development emerged on physical well-being. Early stressful events negatively affect long-term children's emotional and physical well-being while a positive CVT development seems to mitigate the negative effects of early stressful events on physical well-being.

A Critical Review of Ultra-Short-Term Heart Rate Variability Norms Research

Heart rate variability (HRV) is the fluctuation in time between successive heartbeats and is defined by interbeat intervals. Researchers have shown that short-term (∼5-min) and long-term (≥24-h) HRV measurements are associated with adaptability, health, mobilization, and use of limited regulatory resources, and performance. Long-term HRV recordings predict health outcomes heart attack, stroke, and all-cause mortality. Despite the prognostic value of long-term HRV assessment, it has not been broadly integrated into mainstream medical care or personal health monitoring. Although short-term HRV measurement does not require ambulatory monitoring and the cost of long-term assessment, it is underutilized in medical care. Among the diverse reasons for the slow adoption of short-term HRV measurement is its prohibitive time cost (∼5 min). Researchers have addressed this issue by investigating the criterion validity of ultra-short-term (UST) HRV measurements of less than 5-min duration compared with short-term recordings. The criterion validity of a method indicates that a novel measurement procedure produces comparable results to a currently validated measurement tool. We evaluated 28 studies that reported UST HRV features with a minimum of 20 participants; of these 17 did not investigate criterion validity and 8 primarily used correlational and/or group difference criteria. The correlational and group difference criteria were insufficient because they did not control for measurement bias. Only three studies used a limits of agreement (LOA) criterion that specified a priori an acceptable difference between novel and validated values in absolute units. Whereas the selection of rigorous criterion validity methods is essential, researchers also need to address such issues as acceptable measurement bias and control of artifacts. UST measurements are proxies of proxies. They seek to replace short-term values which, in turn, attempt to estimate long-term metrics. Further adoption of UST HRV measurements requires compelling evidence that these metrics can forecast real-world health or performance outcomes. Furthermore, a single false heartbeat can dramatically alter HRV metrics. UST measurement solutions must automatically edit artifactual interbeat interval values otherwise HRV measurements will be invalid. These are the formidable challenges that must be addressed before HRV monitoring can be accepted for widespread use in medicine and personal health care.

Sustained Attention and Individual Differences in Adolescents' Mood and Physiological Reactivity to Stress

Biased attention to sad faces is associated with depression in adults and is hypothesized to increase depression risk specifically in the presence, but not absence, of stress by modulating stress reactivity. However, few studies have tested this hypothesis, and no studies have examined the relation between attentional biases and stress reactivity during adolescence, despite evidence that this developmental window is marked by changes in depression risk, stress, and the function of attention. Seeking to address these limitations, the current study examined the impact of adolescents' sustained attention to facial displays of emotion on individual differences in both mood reactivity to real-world stress and physiological (i.e., respiratory sinus arrhythmia [RSA]) reactivity to a laboratory-based stressor. Consistent with vulnerability-stress models of attention, greater sustained attention to sad faces was associated with greater depressive reactions to real-world stress. In addition, there was preliminary evidence from exploratory analyses that the impact of sustained attention on mood and/or physiological reactivity may be moderated by adolescents' age and sex such that relations are stronger for older adolescents and girls. The results of this study contribute to the current body of research on the role of attention in stress reactivity and depression risk and highlight the importance of considering age differences when examining these relations.

Higher Anxiety Is Associated with Lower Cardiovascular Autonomic Function in Female Twins

Anxiety symptoms co-occur with cardiovascular health problems, with increasing evidence suggesting the role of autonomic dysfunction. Yet, there is limited behavior genetic research on underlying mechanisms. In this twin study, we investigated the phenotypic, genetic and environmental associations between a latent anxiety factor and three cardiovascular autonomic function factors: interbeat interval (IBI, time between heart beats), heart rate variability (HRV, overall fluctuation of heart-beat intervals) and baroreflex sensitivity (BRS, efficiency in regulating blood pressure [BP]). Multivariate twin models were fit using data of female twins (N = 250) of the Twin Interdisciplinary Neuroticism Study (TWINS). A significant negative association was identified between latent anxiety and BRS factors (r = -.24, 95% CI [-.40, -.07]). Findings suggest that this relationship was mostly explained by correlated shared environmental influences, and there was no evidence for pleiotropic genetic or unique environmental effects. We also identified negative relationships between anxiety symptoms and HRV (r = -.17, 95% CI [-.34, .00]) and IBI factors (r = -.13, 95% CI [-.29, .04]), though these associations did not reach statistical significance. Findings implicate that higher anxiety scores are associated with decreased efficiency in short-term BP regulation, providing support for autonomic dysfunction with anxiety symptomatology. The baroreflex system may be a key mechanism underlying the anxiety-cardiovascular health relationship.

Associations Between Teachers' Autonomic Dysfunction and Voice Complaints

OBJECTIVE

This investigation aimed to verify if there were any differences in autonomic nervous system function and voice parameters of teachers with and without voice complaints.

STUDY DESIGN

Cross-sectional study.

METHODS

The Questionnaire of Autonomic Dysfunction was answered by 24 teachers, 6 males, and 18 females, whose heart rate variability was also assessed. Aerodynamic assessment of voice, acoustic and auditory-perceptual analysis of voice were done. Participants were divided into two groups: without voice complaints (WVCG; n = 11) and with voice complaints (VCG; n = 13) based on the completion of the Sociodemographic and Clinical Questionnaire.

RESULTS

For auditory-perceptual analysis, VCG showed significantly higher values on GRBASH subscales Grade (P < 0.001) and Roughness (P = 0.011). Regarding the heart rate variability, it was found that in the VCG, the square root of the mean squared difference of successive RR intervals (RMSSD) and the percentage of adjacent NN intervals differing by more than 50 milliseconds (pNN50) were significantly lower than in the WVCG (P = 0.023 and P = 0.032, respectively). The VCG presented a higher occurrence of neurovegetative symptoms directly related to voice, namely in fluctuating nose obstruction (P = 0.011), neck pain (while or after speaking) (P = 0.017) and in fatigability when speaking (P = 0.004). Concerning the aerodynamic assessment of voice, acoustic analysis of voice and neurovegetative symptoms not directly related to voice, no statistically significant differences between groups were found.

CONCLUSIONS

Findings indicated significantly lower values in RMSSD and pNN50 of teachers VCG when compared with teachers WVCG and that the teachers VCG presented a higher occurrence of neurovegetative symptoms directly related to voice than the ones WVCG.

Is Dispositional Self-Compassion Associated With Psychophysiological Flexibility Beyond Mindfulness? An Exploratory Pilot Study

BACKGROUND

Dispositional mindfulness and self-compassion are shown to associate with less self-reported emotional distress. However, previous studies have indicated that dispositional self-compassion may be an even more important buffer against such distress than dispositional mindfulness. To our knowledge, no study has yet disentangled the relationship between dispositional self-compassion and mindfulness and level of psychophysiological flexibility as measured with vagally mediated heart rate variability (vmHRV). The aim was thus to provide a first exploratory effort to expand previous research relying on self-report measures by including a psychophysiological measure indicative of emotional stress reactivity.

METHODS

Fifty-three university students filled out the "Five Facet Mindfulness Questionnaire" (FFMQ) and the "Self-Compassion Scale" (SCS), and their heart rate was measured during a 5 min resting electrocardiogram. Linear hierarchical regression analyses were conducted to examine the common and unique variance explained by the total scores of the FFMQ and the SCS on level of resting vmHRV.

RESULTS

Higher SCS total scores associated significantly with higher levels of vmHRV also when controlling for the FFMQ total scores. The SCS uniquely explained 7% of the vmHRV. The FFMQ total scores did not associate with level of vmHRV.

CONCLUSION

These results offer preliminary support that dispositional self-compassion associates with better psychophysiological regulation of emotional arousal above and beyond mindfulness.

Trusting your heart: Long-term memory for bad and good people is influenced by resting vagal tone

Several studies have highlighted the role of heart rate variability (HRV) in social engagement and social cognition. However, whether HRV is involved in the ability to remember faces associated with affectively salient behavioural information remains unexplored. The present study aims to close this gap by investigating long-term face-memory accuracy in individuals differing in resting vagally-mediated HRV. Individuals with high or low resting HRV viewed faces associated with episodic information differing in affective valence (positive, neutral, negative) or without any behavioural description. After one week, a face recognition test was administered. High HRV individuals were better at recognizing faces paired with positive and negative behavioural descriptions compared to neutral faces or faces without descriptions. Conversely, low HRV participants did not show any face memory advantage from personal information. The present results suggest that HRV may provide a novel biological marker of long-term face recognition.

A psychophysiological investigation of the interplay between orienting and executive control during stimulus conflict: A heart rate variability study

BACKGROUND

It has been hypothesized that resting state cardiac vagal activity (CVA) - an indicator of parasympathetic nervous system activity - is a specific psychophysiological marker of executive control function. Here, we propose an alternative hypothesis - that CVA is associated with early stage attention orientation, promoting the flexible uptake of new information, on which the later operation of such executive control functions depends. We therefore predicted that CVA would predict the interaction between orienting and executive control. This was tested using the revised version of the Attention Network Test (ANT-R) that was developed to distinguish between orienting and executive attention during a stimulus conflict task.

METHODS

Healthy adults (N = 48) performed the ANT-R and their resting CVA was measured over a 5 min period using ECG recordings.

RESULTS

Multiple regression analyses indicated that, when other factors were controlled for, CVA was more strongly associated with the interaction between the orienting and executive control terms than with either factor individually.

CONCLUSION

Higher levels of CVA are specifically implicated in the modulation of executive control by intrinsic orientation operating at early stages of conflict detection. These initial findings of higher CVA on orienting attention in conflict detection need to be replicated in larger samples.

Heart Rate Variability reveals the fight between racially biased and politically correct behaviour

In this study, we explored vagally-mediated heart rate variability (vmHRV) responses, a psychophysiological index of cognitive self-regulatory control, to map the dynamics associated with empathic responses for pain towards an out-group member. Accordingly, Caucasian participants were asked to judge the experience of African and Caucasian actors touched with either a neutral or a harmful stimulus. Results showed that (1) explicit judgment of pain intensity in African actors yielded higher rating score and (2) took longer time compared to Caucasian actors, (3) these behavioural outcomes were associated with a significant increment of RMSSD, Log-HF-HRV and HF-HRV n.u., (4) resting HF-HRV n.u. predicted the participants’ lag-time to judge painful stimulations delivered to African actors. Interestingly, these dynamics were associated with a measure of implicit racial attitudes and were, in part, abolished when participants performed a concurrent task during videos presentation. Taken together our results support the idea that a cognitive effort is needed to self-regulate our implicit attitude as predicted by the ‘Contrasting Forces Model’.

Resting heart rate variability is negatively associated with mirror neuron and limbic response to emotional faces

Whether neurovisceral integration, reflected by resting high-frequency heart rate variability (HRV), constrains or facilitates neural reactivity to other people's emotions is unclear. We assessed the relation between resting HRV and neural activation when observing and imitating emotional faces. We focused on brain regions implicated in sensorimotor resonance, salience detection and arousal. We used electrocardiogram data to compute resting HRV. Resting HRV measures were negatively correlated with activation in a portion of the inferior frontal gyrus showing mirror neuron properties, the insula and the amygdala in response to observation, but not imitation, of emotional faces. Thus, resting HRV appears to be linked to sensitivity to others' emotional cues, both in terms of the tendency to map others' emotional facial expressions onto one's own motor system and to rapidly detect and mark others' emotions as salient events. Resting HRV may reflect, in part, a threshold for increased processing of others' emotional cues.

Heart rate increase predicts challenging behavior episodes in preschoolers with autism

Identifying triggers for challenging behavior is difficult in some children with autism because of their limited communication abilities. Physiological indicators of stress may provide important insights. This study examined whether heart rate (HR) predicts challenging behavior in children with autism. While wearing an electrocardiograph monitor, 41 children with autism aged 2- to 4-years participated in tasks designed to induce low-level stress (e.g. waiting for a snack). Coders identified 106 time periods during which challenging behaviors occurred and also coded 106 randomly selected time samples that did not include challenging behaviors. Thirteen (32%) participants exhibited challenging behaviors and were included in the study. Baseline-corrected HR was computed for each behavior/time sample. On average, children with autism showed a 22 ± 16% HR increase from baseline 58 ± 22 seconds before the onset of a challenging behavior episode. Peak HR change had moderate predictive utility (area under the curve = .72, p < .001). The increase in HR before challenging behaviors was similar for children of different characteristics (age, autism severity, expressive language ability, overall developmental ability). Results highlight the promise of using physiological stress to predict challenging behavior in preschoolers with autism; although, they need to be replicated in larger samples. Given recent advances in wearable biosensing, it may be useful to incorporate HR monitoring in autism intervention. Lay summary In children with autism, changes in heart rate (HR) may help us predict when challenging behavior is about to occur - but this hypothesis has not been well studied. In this study, HR increase moderately predicted challenging behavior in preschoolers with autism. Given recent advances in wearable sensors, it may be useful to incorporate HR monitoring in autism intervention.

A Novel Wearable EEG and ECG Recording System for Stress Assessment

Suffering from continuous stress can lead to serious psychological and even physical disorders. Objective stress assessment methods using noninvasive physiological responses such as heart rate variability (HRV) and electroencephalograms (EEG) have therefore been proposed for effective stress management. In this study, a novel wearable device that can measure electrocardiograms (ECG) and EEG simultaneously was designed to enable continuous stress monitoring in daily life. The developed system is easily worn by hanging from both ears, is lightweight (i.e., 42.5 g), and exhibits an excellent noise performance of 0.12 μVrms. Significant time and frequency features of HRV and EEG were found in two different stressors, namely the Stroop color word and mental arithmetic tests, using 14 young subjects. Stressor situations were classified using various HRV and EEG feature selections and a support vector machine technique. The five-fold cross-validation results obtained when using both EEG and HRV features showed the best performance with an accuracy of 87.5%, which demonstrated the requirement for simultaneous HRV and EEG measurements.

Sex differences in stress-related alcohol use

Rates of alcohol use disorder (AUD) have increased in women by 84% over the past ten years relative to a 35% increase in men. This substantive increase in female drinking is alarming given that women experience greater alcohol-related health consequences compared to men. Stress is strongly associated with all phases of alcohol addiction, including drinking initiation, maintenance, and relapse for both women and men, but plays an especially critical role for women. The purpose of the present narrative review is to highlight what is known about sex differences in the relationship between stress and drinking. The critical role stress reactivity and negative affect play in initiating and maintaining alcohol use in women is addressed, and the available evidence for sex differences in drinking for negative reinforcement as it relates to brain stress systems is presented. This review discusses the critical structures and neurotransmitters that may underlie sex differences in stress-related alcohol use (e.g., prefrontal cortex, amygdala, norepinephrine, corticotropin releasing factor, and dynorphin), the involvement of sex and stress in alcohol-induced neurodegeneration, and the role of ovarian hormones in stress-related drinking. Finally, the potential avenues for the development of sex-appropriate pharmacological and behavioral treatments for AUD are identified. Overall, women are generally more likely to drink to regulate negative affect and stress reactivity. Sex differences in the onset and maintenance of alcohol use begin to develop during adolescence, coinciding with exposure to early life stress. These factors continue to affect alcohol use into adulthood, when reduced responsivity to stress, increased affect-related psychiatric comorbidities and alcohol-induced neurodegeneration contribute to chronic and problematic alcohol use, particularly for women. However, current research is limited regarding the examination of sex in the initiation and maintenance of alcohol use. Probing brain stress systems and associated brain regions is an important future direction for developing sex-appropriate treatments to address the role of stress in AUD.

[Heart Rate Variability - State of Research and Clinical Applicability]

Heart Rate Variability - State of Research and Clinical Applicability Abstract. Heart rate variability is considered a marker of autonomous nervous system activity. Autonomic imbalance is found as a common component in a wide range of pathologies. It has been found to precede the onset of pathologic states and correlates with therapy response. In addition, heart rate variability at rest is a psychophysiological phenomenon with broad significance. Psychological experience affects physiological homeostasis, including immune processes, via the autonomous nerve system, which biologically underpins psychosomatic effects and makes them measurable by heart rate variability. The autonomous nerve system as the interface of this psychophysiological regulation is becoming increasingly important in heart rate variability research and allows a better understanding of the interactions between psyche, lifestyle, autonomous regulation and chronic illness. It requires a systemic, cross-organ view as well as an orientation towards long-term processes. The assessment and normalization of autonomic imbalance thus represents a novel therapeutic strategy from which numerous interventions and lifestyle modifications can be derived. Interventions that strengthen the vagal tone (aerobic or moderate physical training, relaxation techniques, vagus nerve stimulation, etc.) are becoming increasingly important. Despite the simple non-invasive measurement and popularity as a research instrument, interpretation is complex, and clinical implementation has been reluctant so far. Nevertheless, guidelines and data sets of reference values exist for users to apply.

Body mass index and parasympathetic nervous system reactivity and recovery following graded exercise

OBJECTIVES

The present study sought to expand upon prior investigations examining patterns of vagally mediated heart rate variability (vmHRV) and perceived exertion as a function of body mass index (BMI) in response to and recovery from exercise.

METHODS

Participants underwent a resting (baseline) period, followed by a graded exercise protocol on an ergometer with ascending difficulty stages, and finally another resting (recovery) period. Individuals were stratified into three BMI groups: low, moderate, and high.

RESULTS

Individuals in the high BMI group exhibited a significantly greater decrease in vmHRV from baseline to graded exercise in comparison to the moderate BMI group. Individuals in the high BMI group also showed significantly lower vmHRV at recovery compared with baseline than individuals with moderate BMI; indicating that the high BMI group's vmHRV did not recover to the degree of those in the moderate BMI group. No significant results regarding vmHRV were found in the low BMI group. Of note, BMI and perceived exertion during the recovery period were positively associated. Results also showed a significant negative association between vmHRV and perceived exertion at each grade of exercise. There was no significant association between vmHRV and perceived exertion during baseline or recovery.

CONCLUSIONS

This report extends prior research studying BMI and patterns of vmHRV reactivity in the domain of physical exercise. Our data contribute to previous reports suggesting that high BMI can lead to maladaptive patterns of vmHRV reactivity to and recovery from physical exercise.

The effects of physical vibration on heart rate variability as a measure of drowsiness

We investigated the effects of low frequency whole body vibration on heart rate variability (HRV), a measure of autonomic nervous system activation that differentiates between stress and drowsiness. Fifteen participants underwent two simulated driving tasks for 60 min each: one involved whole-body 4-7 Hz vibration delivered through the car seat, and one involved no vibration. The Karolinska Sleepiness Scale (KSS), a subjective measure of drowsiness, demonstrated a significant increase in drowsiness during the task. Within 15-30 min of exposure to vibration, autonomic (sympathetic) activity increased (p < .01) in response to the stress of maintaining alertness and performance when drowsy, and peaked at 60 min (p < .001). Changes in three other HRV domains [higher LF/HF ratios, lower RMSSD (ms) and pNN50 (%) values] were consistent with increased sympathetic activation. These findings have implications for the future development of equivalent drowsiness contours leading to improvements in road safety. Practitioner summary: The effects of physical vibration on driver drowsiness have not been well investigated. This laboratory-controlled study found characteristic changes in heart rate variability (HRV) domains that indicated progressively increasing neurological effort in maintaining alertness in response to low frequency vibration, which becomes significant within 30 min.

ABBREVIATIONS

ANS: autonomic nervous system; Ctrl: control; EEG: electroencephalography; HF: the power in high frequency range (0.15 Hz-0.4Hz) in the PSD relected parasympathetic activity only; HRV: heart rate variability; KSS: karolinska sleepiness scale; LF: the power in low frequency range (0.04 Hz-0.15Hz) in the PSD reflected both sympathetic and parasympathetic activity of the autonomic nervous system; LF/HF ratio: the ratio of LF to HF indicated the balance between sympathetic and parasympathetic activity; RMSSD: the root mean square of difference of adjacent RR interval; pNN50: the number of successive RR interval pairs that differed by more than 50 ms divided by the total number of RR intervals; RR interval: the differences between successive R-wave occurrence times; PSD: power spectral density; RTP: research training program; SD: standard deviation; SEM: standard error of the Mean; Vib: vibration.

Heart Rate and Heart Rate Variability in Parents at Risk for Child Physical Abuse

The present study examined heart rate and heart rate variability (i.e., respiratory sinus arrhythmia [RSA]) in a sample of 48 general population parents (41.7% fathers), who were either at high risk (n = 24) or low risk (n = 24) for child physical abuse. During baseline assessments of heart rate and RSA, parents sat quietly for 3 min. Afterward, parents were presented with a series of anagrams (either easy or difficult) and were instructed to solve as many anagrams as possible in 3 min. As expected, high-risk (compared with low-risk) parents evinced significantly higher resting heart rate and significantly lower resting RSA. During the anagram task, high-risk parents did not evince significant changes in heart rate or RSA relative to baseline levels. In contrast, low-risk parents evinced significant increases in heart rate and significant decreases in RSA during the anagram task. Contrary to expectations, the anagram task difficulty did not moderate the study findings. Collectively, this pattern of results is consistent with the notion that high-risk parents have chronically higher levels of physiological arousal relative to low-risk parents and exhibit less physiological flexibility in response to environmental demands. High-risk parents may benefit from interventions that include components that reduce physiological arousal and increase the capacity to regulate arousal effectively.

Are ultra-short heart rate variability features good surrogates of short-term ones? State-of-the-art review and recommendations

Ultra-short heart rate variability (HRV) analysis refers to the study of HRV features in excerpts of length <5 min. Ultra-short HRV is widely growing in many healthcare applications for monitoring individual's health and well-being status, especially in combination with wearable sensors, mobile phones, and smart-watches. Long-term (nominally 24 h) and short-term (nominally 5 min) HRV features have been widely investigated, physiologically justified and clear guidelines for analysing HRV in 5 min or 24 h are available. Conversely, the reliability of ultra-short HRV features remains unclear and many investigations have adopted ultra-short HRV analysis without questioning its validity. This is partially due to the lack of accepted algorithms guiding investigators to systematically assess ultra-short HRV reliability. This Letter critically reviewed the existing literature, aiming to identify the most suitable algorithms, and harmonise them to suggest a standard protocol that scholars may use as a reference in future studies. The results of the literature review were surprising, because, among the 29 reviewed papers, only one paper used a rigorous method, whereas the others employed methods that were partially or completely unreliable due to the incorrect use of statistical tests. This Letter provides recommendations on how to assess ultra-short HRV features reliably and proposes an inclusive algorithm that summarises the state-of-the-art knowledge in this area.

Altered autonomic reactivity in Korean military soldiers with adjustment disorder

Only few studies addressing the biological background of adjustment disorder (AD) exist. We examined the psychophysiological correlates indicative of autonomic regulation in AD. Heart rate variability (HRV), skin conductance, skin temperature, electromyography, and respiration were measured during serial stress tasks in 33 soldiers with AD and 60 healthy controls (HC). Patients with AD displayed lower relative power of high frequency (rHF) HRV and higher relative power of very low frequency (rVLF) HRV compared with HC at baseline. Inversely, the rHF of patients with AD remained higher and their rVLF remained lower compared with HC parameters after the single stress task, which suggests a reversed sympathovagal balance in AD. Mean heart rate and skin conductance increased during stress tasks in patients, although to a lesser extent than in HC. Skin temperature remained unchanged in all tasks in patients with AD. The tension of the frontalis muscle was higher in patients compared with HC from the second stress task onward. Thoracic breathing was more prevalent in patients with AD. Our study suggests altered autonomic reactivity in AD, which leads to a lack of sympathetic response to stress. We conclude that the distinctive biological mechanisms underlying AD are different from normal stress reactions.